Ranaivomanana Paulo, Raharimanga Vaomalala, Dubois Patrice M, Richard Vincent, Rasolofo Razanamparany Voahangy
Mycobacteria Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar.
Epidemiology Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar.
PLoS One. 2015 Jul 27;10(7):e0127590. doi: 10.1371/journal.pone.0127590. eCollection 2015.
Although the Bacillus Calmette-Guérin vaccine (BCG) protects young children against serious forms of TB, protection against pulmonary TB is variable. We assessed BCG vaccine-induced cellular immune responses and determined for how long they could be detected during childhood in Antananarivo, Madagascar.
We assessed BCG vaccine-induced cellular immune responses by TST and IGRA (in-house ELISPOT assay) using BCG and PPD as stimulation antigen, and compared results between vaccinated and non-vaccinated schoolchildren of two age groups, 6-7 and 13-14 years old.
Three hundred and sixty-three healthy schoolchildren were enrolled. TST was performed on 351 children and IGRA on 142. A high proportion (66%; 229/343) of the children had no TST reactivity (induration size 0 mm). TST-positive responses (≥15 mm) were more prevalent among 13-14 year-old (31.7%) than 6-7 year old (16.5%) children, both in the non-vaccinated (43% vs. 9%, p<0.001) and vaccinated (29% vs. 13%, p=0.002) subgroups. There were no significant differences in TST responses between vaccinated and non-vaccinated children in either of the age groups. The IGRA response to BCG and to PPD stimulation was not significantly different according to BCG vaccination record or to age group. A high rate (15.5%; 22/142) of indeterminate IGRA responses was observed. There was very poor agreement between TST and IGRA-PPD findings (k= 0.08) and between TST and IGRA-BCG findings (k= 0.02).
Analysis of TST and IGRA response to stimulation with BCG and PPD revealed no difference in immune response between BCG-vaccinated and non-vaccinated children; also no decrease of the BCG vaccine-induced cellular immune response over time was observed. We conclude that TST and IGRA have limitations in assessing a role of BCG or tuberculosis-related immunity.
尽管卡介苗（BCG）可保护幼儿免受严重形式的结核病侵害，但对肺结核的保护作用存在差异。我们评估了卡介苗诱导的细胞免疫反应，并确定在马达加斯加塔那那利佛儿童期能检测到这些反应的时长。
我们通过结核菌素皮肤试验（TST）和干扰素-γ释放试验（IGRA，内部酶联免疫斑点试验），以卡介苗和纯蛋白衍生物（PPD）作为刺激抗原，评估卡介苗诱导的细胞免疫反应，并比较了两个年龄组（6-7岁和13-14岁）接种疫苗和未接种疫苗的学童之间的结果。
共纳入363名健康学童。对351名儿童进行了TST检测，对142名儿童进行了IGRA检测。很大一部分儿童（66%；229/343）的TST无反应性（硬结大小为0毫米）。在未接种疫苗（43%对9%，p<0.001）和接种疫苗（29%对13%，p=0.002）的亚组中，13-14岁儿童（31.7%）的TST阳性反应（≥15毫米）比6-7岁儿童（16.5%）更普遍。在两个年龄组中，接种疫苗和未接种疫苗的儿童之间的TST反应均无显著差异。根据卡介苗接种记录或年龄组，IGRA对卡介苗和PPD刺激的反应无显著差异。观察到较高比例（15.5%；22/142）的IGRA反应不确定。TST与IGRA-PPD结果之间（k=0.08）以及TST与IGRA-卡介苗结果之间（k=0.02）的一致性非常差。
对卡介苗和PPD刺激的TST和IGRA反应分析显示，接种卡介苗和未接种卡介苗的儿童之间的免疫反应无差异；也未观察到卡介苗诱导的细胞免疫反应随时间下降。我们得出结论，TST和IGRA在评估卡介苗或结核病相关免疫的作用方面存在局限性。
